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Photo Engineer
12-10-2010, 04:55 PM
There are several points here to address.

Knowing the ingredients does not tell you anything about how or when they got into the film. AgX is correct!

Analysis may not tell you what all is there, especially when some trace elements are there at very low levels. You cannot, a priori, say if it is there deliberately or is there as an impurity.

I have read the Brovira formula and have devised a Kodabromide like formula of my own. There is little similarity between the two formulas. The latter, mine, will be included in my book. I did not include the Brovira formula. My formula is doped with Rhodium Chloride at about 10^-6 moles of Rhodium per mole of silver. You can see how low that level is and how difficult it would be to detect in most analyses.

Both Kodak and Agfa used Rhodium salts for contrast control just as I do in my formula. Nowdays, Kodak uses organic compounds which were unavailable to me.

I have no information as to what plans might be in place if Kodak stops production of analog products, but I would ask the same question of Fuji and Ilford as a rhetorical question. After all, where really are the Agfa formulas for their color papers and films and what might happen to the Ilfocolor formulas if they stop production?

PE

Mustafa Umut Sarac
12-10-2010, 05:11 PM
PE ,

Where did you find the Brovira Formula , is it patent , open or archive document ?

I think testing different batches of same paper tells what is impurity , what is for real.

Umut

dwross
12-10-2010, 05:30 PM
Where did you find the Brovira Formula , is it patent , open or archive document ?


'Photographic Chemistry', Volume One, by Pierre Glafkides, 1957, pp 342-343. Five grades: Extra Hard, Hard, Normal, Special, and Soft.

Mustafa Umut Sarac
12-10-2010, 05:40 PM
dwross ,

Can you copy and write here what is reported at these two pages

Umut

michaelbsc
12-10-2010, 05:43 PM
PE, are you serious that I can probably make pan 400ISO sheets at home given the techniques?

And that I can make a color sheet film as well? At what speed? I assume this is a negative without orange mask?

dwross
12-10-2010, 05:49 PM
dwross ,

Can you copy and write here what is reported at these two pages

Umut

The Glafkides book, at least the chapters on emulsion making, are next but one on my scanning and posting schedule for TLF. I'm currently working on 'Successful Negative Making', by T. Thorne Baker.

Mustafa Umut Sarac
12-10-2010, 06:00 PM
Thank you dwross.

I am waiting your Agfa Scans.

Umut

Mustafa Umut Sarac
12-10-2010, 06:03 PM
AgfaPhoto is the new company responsible for the photographic products.

I sent to a message asking archive research.

Monday or Tuesday answer could appear at my mailbox and I will be here.

Photo Engineer
12-10-2010, 06:07 PM
PE ,

Where did you find the Brovira Formula , is it patent , open or archive document ?

I think testing different batches of same paper tells what is impurity , what is for real.

Umut

I had access to the BIOS and FIAT reports of WWII. They are at the GEH, RIT and EK libraries IIRC. The formula has changed little over the years except for keeping and reciprocity chemistry.

PE

Photo Engineer
12-10-2010, 06:12 PM
PE, are you serious that I can probably make pan 400ISO sheets at home given the techniques?

And that I can make a color sheet film as well? At what speed? I assume this is a negative without orange mask?

Yes, you could probably make an ISO 400 emulsion, but I think that you would find that making glass plates would be better than film.

The color material would probably be a dye bleach material and would give slides. They would be very grainy and the film would be slow. A coupler based system would be harder to devise due to the need for custom chemistry. The couplers are just not available. A Kodachrome like product would be easier to make in some respects but harder to process.

PE

michaelbsc
12-10-2010, 06:17 PM
PE, are you serious that I can probably make pan 400ISO sheets at home given the techniques?

And that I can make a color sheet film as well? At what speed? I assume this is a negative without orange mask?

Yes, you could probably make an ISO 400 emulsion, but I think that you would find that making glass plates would be better than film.

The color material would probably be a dye bleach material and would give slides. They would be very grainy and the film would be slow. A coupler based system would be harder to devise due to the need for custom chemistry. The couplers are just not available. A Kodachrome like product would be easier to make in some respects but harder to process.

PE

So what part of this was I expecting to be easy?

MB

Q.G.
12-10-2010, 06:19 PM
Can you copy and write [...]

dwross,

I too don't want to sidetrack this thread, but a word of warning: those two highlighted words spelled a bit differently, and page 4 of the scanned book, can get you in serious (and expensive) trouble.

michaelbsc
12-10-2010, 06:20 PM
Dry plates I assume? Therefore transportable.

Photo Engineer
12-10-2010, 06:20 PM
Sometime about 1630, Samuel Pepys had a golf ball sized stone removed from his bladder by surgery. He was one of the few people who survived surgery in those days. If you had to have a stone removed, would you choose the surgical method used on him, or a modern method?

:D

I know, I know, this sounds stupid, but the fact remains that all works published on emulsion making that are dated before about 1940 have a similar relationship regarding both theory and practice to the example in my first paragraph. Even the FIAT and BIOS reports show emulsions that give some very nice products but are quite primitive. You will find that the old reports described in German, use the word "gekippt" which means that the ingredients were "tipped" or "dumped" into the reactor to make an emulsion. Well, one of the great advances that introduced constant and repeatable speeds was the use of pumps!

Ok, then take this a step at a time. A better mixer gave better uniformity. Subsurface addition of ingredients removed the effects of foam, dual running of salt and silver gave better curve shape. Baker and Wall, and even Carroll knew nothing about these things in 1940! Can you do any or all of these in your darkroom? Of course you can! And that is part of my point here.

PE

michaelbsc
12-10-2010, 06:24 PM
Sometime about 1630, Samuel Pepys had a golf ball sized stone removed from his bladder by surgery. He was one of the few people who survived surgery in those days. If you had to have a stone removed, would you choose the surgical method used on him, or a modern method?

:D

I know, I know, this sounds stupid, but the fact remains that all works published on emulsion making that are dated before about 1940 have a similar relationship regarding both theory and practice to the example in my first paragraph. Even the FIAT and BIOS reports show emulsions that give some very nice products but are quite primitive. You will find that the old reports described in German, use the word "gekippt" which means that the ingredients were "tipped" or "dumped" into the reactor to make an emulsion. Well, one of the great advances that introduced constant and repeatable speeds was the use of pumps!

Ok, then take this a step at a time. A better mixer gave better uniformity. Subsurface addition of ingredients removed the effects of foam, dual running of salt and silver gave better curve shape. Baker and Wall, and even Carroll knew nothing about these things in 1940! Can you do any or all of these in your darkroom? Of course you can! And that is part of my point here.

PE

And I know for a fact that I'm not the only process control guy around here.

Photo Engineer
12-10-2010, 06:24 PM
Dry plates I assume? Therefore transportable.

Absolutely dry plates. Keeping at the present time is about 1 year for the uncoated emulsions and 1 year for the coated materials. I can do better, but there is just so much time to experiment and write.

PE

Photo Engineer
12-10-2010, 06:27 PM
And I know for a fact that I'm not the only process control guy around here.

I've found that you don't need full control with feedback loops. You just need a high impedence meter with the right electrodes and a syringe of salt to poke the vAg back into control. You see, salt rate needs to rise over an addition just to keep the salt in balance. The vAg is the measure of salt, and therefore you can just add salt from a syringe dropwise to keep the millivolts constant with your needs.

No computer is needed.

PE

Mustafa Umut Sarac
12-10-2010, 06:31 PM
Ron ,

I found your old post archives.

Here is the Brovira Formulas Link :

http://lostlabours.co.uk/Uploads/brovira.jpg

Hexavalent
12-10-2010, 06:34 PM
I've found that you don't need full control with feedback loops. ...

PE

But, a geek like me cannot resist the beauty of a well-tuned analog PID controller :)

Photo Engineer
12-10-2010, 06:55 PM
The post above on Brovira was not mine. Both Ian Grant and I posted Brovira variants in a thread here about a year or so ago.

I would add that the formulas above do NOT explicity give the types of active gelatin used. Each grade of early Brovira and Kodabromide used a different type of gelatin tailored for the contrast grade. So the formulas above would either have to use old style gelatin blends or be revised for modern chemical sensitization methods. Also, Brovira did use Rhodium Chloride IIRC.

PE